A common problem encountered by operators of drive-track type snowmobiles is the freezing of the drive track to the slide rails which can occur due to parking the vehicle for a period of time after usage. Snow and ice that have attached to the snowmobile during the riding period may melt due to temperature conditions, and refreezing of the melted snow and ice can occur given appropriate conditions, resulting in the drive track becoming frozen to the slide rails. Another problem facing snowmobile operators is the recommendation of manufacturers that their vehicles be raised above the ground surface to warn up the drive train prior to initial attempts to move the vehicle; this relates to the need to prevent drive belt wear and disintegration.
Both of these problems facing snowmobile operators can be addressed by employing means of raising the drive track above the ground surface for a desired period. However, potential solutions to these problems are complicated by the weight of commercially available snowmobiles, which can be as much as 700 pounds. Lifting a vehicle of such considerable size is a difficult task. It is also extremely dangerous, as the vehicle must be held up with one hand while a support is positioned beneath the vehicle with the other hand.
It is not uncommon to see snowmobiles propped up on wood crates or the like as supports that are perceived as adequate for elevating the vehicle drive track. However, there are serious safety concerns with such a practice, as the operator must engage in strenuous and potentially harmful manual lifting of the vehicle rear to rest it upon the crate, and the crate is likely not a thoroughly stable support apparatus in any event. Lack of a stable support could result in the vehicle falling from the elevated position, potentially causing damage to the vehicle and its surroundings and injury to bystanders. In addition, using such a method when warming up the vehicle prior to operation could result in further potential damage from the vehicle surging forward upon support collapse.
Prior attempts to address these problems include a variety of devices such as stands and jacks. Many of these devices are separate from the vehicle, however, and may not be available when needed due to susceptibility to loss or lack of storage space on the vehicle There are a handful of devices that are capable of attachment to the snowmobile itself, such as U.S. Pat. No. 3,981,372 to Moreau and U.S. Pat. No. 3,785,541 to Sibley. However, most of these devices fail to provide the vehicle operator with relief from the physical stresses involved in lifting or rocking their vehicles into the raised position.
In addition, another concern remains in that the snowmobile is susceptible to tipping once it is moved into the lifted position, as many of the lifting mechanisms become highly unstable once extended. When a snowmobile is raised off of the ground at the rear and is supported only by the lifting mechanism and front skis, the stability of the vehicle is jeopardized. As the skis can readily pivot, the snowmobile is balanced precariously on these skis and the extended, unstable lifting mechanism. In such a situation, the snowmobile may topple to one side or the other, a problem exacerbated by the fact that the skis are designed to slide in the underlying snow and may assist in the toppling by allowing the weight of the snowmobile to shift forward or backward.
While lifting mechanisms for vehicles such as four-wheeled automobiles can allow for a certain degree of instability due to the over-all stability of the automobile itself, snowmobiles are designed in such a way that this instability is a significant problem, and toppling of the snowmobile due to unstable lifting mechanisms can lead to vehicle damage or operator injury.